LED strips are flexible and can be cut to measure and have many indoor and outdoor applications. FIG. 1 shows a schematical diagram of a typical embodiment of a known LED strip. Two strips of conductive material extend along the length of the LED strip. During operation a DC supply voltage of for instance 12 Volts is present between these strips. Series arrangements, each comprising a resistor R and a LED string LS, are connected in parallel between the conductive strips. The LED string may comprise one or more LEDs, in the embodiment shown in FIG. 1 three LEDs are comprised in a LED string. The conductive strips, the resistors and the LED strings are all mounted on a flexible PCB and covered with a transparent material or a diffusor. A user can cut the LED strip to a desired length at places indicated by a dotted line.
A disadvantage of the known LED strip is that the electronic circuit of each LED string is not efficient, which also leads to heat development. Furthermore, the LED light output is very sensitive for differences in input voltage.